Sorry to hear about the stain problem Alb. Good luck getting it ironed out.

Riles

Thanks riles. I think my problem is probably that I sanded all of the deck. I used so many screws, and had enough other things to work out that spot sanding did not seem appropriate. The ipe is probably not accepting the stain well, so the tape could do it's thing. The wet concrete off the counter does the same thing, creating light spots.

I'm going to finish the island work, let the elements do their thing for a while, and then re-address the stain. Maybe some reapplication to feather out the light areas, and then time followed by a RAD treatment and stain.

{{!gwi}}{{!gwi}}

Alb,

How thick is the concrete that you poured for the countertop? How is it supported? Just regular concrete mix? I assume you added some sort of shelf under that. Do you do anything special to control cracking or are you planning on covering it. What materials are you using for the backsplash, etc.

Looking good!

Riles

The concrete is 1 1/2" to about 1 3/4". The frame was not perfectly level, but the form was and the top of the counter will be very close to level after grinding. I will play with the bevels (radiuses) on the edges when I grind it to hide the difference in thicknesses of some areas.

Cracking generally occurs in concrete, there are ways to minimize it. Rebar and wire mesh reinforcement, fiber reinforcement, water reducer, high quality, high strength concrete, good foundation, slow curing, a relatively dry (low water mix), etc. 1.5 inch is probably the minimum you would want to use. Ghosting and other issues arise when you go less. My concrete formula is Cheng Design, others like Buddy Rhodes are also well known and cater to the DIYer.

I have 2 1/2 counters in my kitchen that I built off site in forms and then placed on the cabinets. If you have good woodworking skills, this is the way to go because you can get a perfect top surface. This island is poured in place, less steps, but harder to get perfect, but I wanted to try it anyway. The ones in my kitchen have not one hairline crack, but I imagine the one on the deck will show some. I had to use a little more water to allow for troweling, and it's thinner and not as well reinforced. The kitchen is on 3/4 ply, on reinforced ply cabinets, as well as a reinforced floor framing. Out side is on 1/2 Hardibacker.

If you want to learn about building your own concrete counter go to amazon.com and get the book "concrete countertops" by Cheng.

Here are my first counters after reading that book. I'm not sure on the backsplash yet.
{{!gwi}}

Sanding with 80/60 has no effect one way or the other far as ipe taking finish. The 516 twp takes a little longer to set up than the 116. J

that's good news, I think it will be easier to solve in that case. Thanks, John.

TWP finish its in a whole nother plane in the realm of outdoor finish. I have tracked down some info on the stuff and talked to a Guy who worked on it in a chem way for a number of years on the most you wont belive it scale them boys have a 1000 series they put on ipe manholes in S Call people are driving on them as well as the halter tops girls with the roller blades.

Anyway twp has got to be exposed to the sun to set up, I learned this doing shop projects. I am thinking mabey that 516 just dident have enough time before the tape. On the good side its probley right you put it on before doing all that creet work, ipe will turn black with creet droped on it with no protection.

Very good work Bro. J

One more thing, I think that any thicker than 1.5" or so on the concrete deserves 3/4" plywood under it. The last thing you want is for your counter to sag while it dries.

So how did your concrete countertops and deck turn out?

I think they turned out great. I'm still working on some details, and I think I will change the back splash to stone or concrete, but here it is

{{!gwi}}{{!gwi}}.{{!gwi}}{{!gwi}}

Bravo alb!! That looks fabulous. I am very jealous right now because I don't have the cash to do everything that I want so I am in a holding pattern on my island right now.

The concrete countertops came out great. Love the slight hints of red-ish color in the concrete that matches the decking material. Makes it all come together nice.

So how was it doing the countertops in place verses separately? Any tips you care to share about the concrete counter process? How much effort is the polishing part? Does the troweling need to be fairly smooth, or does that just make for easier polishing?

Riles

Al, I know you had some differences of opinion concerning the exposed ss screws, but I think it matches that modern/industrial look with the concrete countertop. Always wanted to do one but have never gotten the courage. Must be something about the civil engineer in me and knowing that concrete has to crack....

Riles, thank you very much. Here is a picture of a form I built off site for my kitchen. I think it explains more than I can write, but I will add some thoughts.{{!gwi}}
Offsite:

more work

needs to be more precise

a template is made on site and then flipped over to lay out the form - the bottom of the off site form becomes the top of the counter

less grinding/polishing needed and troweling is not a critical

knock outs are easier to achieve(sink, faucets, etc)

need help to put in place

much cleaner final product.

Pour in place:

Hard to finish - an experienced troweler helps a lot if not mandatory.

more grinding polishing

wet grinding and polishing makes an incredible mess on site

less than perfect finished product

Tips I would share, buy the book "concrete countertops" by Cheng at Amazon.com. Use a concrete formula specified for countertops (Cheng, Buddy Rhodes, others). Rent or borrow a mixer. buy the book "concrete countertops" by Cheng, I said it twice because it will explain much more than I know.

pmurfe, thanks a lot. I think you should get Cheng's book and you may decide that even as an engineer you want to work with concrete. PS, it's not the same mix as on sidewalks, but it may crack in the end:)